1. Technical Field
Embodiments of the present disclosure may generally relate to semiconductor devices, and more particularly, semiconductor devices relating to testing redundancy regions.
2. Related Art
As semiconductor devices become more highly integrated, a failure rate of memory cells of the semiconductor devices has been increased. This increase in failure rate is because of the increase of the number of the memory cells integrated in a limited area. As a result, the semiconductor devices are designed to include a redundancy circuit in order to increase a yield thereof even though defective memory cells exist after fabrication of the semiconductor devices.
The redundancy circuits include redundancy memory cells and fuses for programming repair addresses corresponding to failed memory cells. If fabrication processes of the semiconductor devices terminate at a wafer level, various tests may be applied to the semiconductor devices to sort repairable chips and to obtain addresses of failed memory cells or defective memory cells in the repairable chips. The addresses corresponding to the failed memory cells may be programmed to replace the failed memory cells of the repairable chips with the redundancy memory cells and to improve the yield of the semiconductor devices.
A fuse programming method may be used to program address information corresponding to the failed memory cells. In general, a laser blowing technique may be used in cutting the fuses. In such cases, the fuses may be physically cut using a laser beam. Accordingly, the laser blowing technique can be applied to the semiconductor devices only at a wafer level before the semiconductor devices are encapsulated to form semiconductor packages.
An electrical fuse bowing technique instead of the physical fuse bowing technique may be required to replace the failed memory cells with the redundancy memory cells at a package level. Fuses which can be programmed at a package level may be generally called electrical fuses. This means that predetermined fuses of the electrical fuses can be selectively cut using only an electrical signal. The electrical fuses may be categorized as either anti-type fuses or blowing-type fuses. The anti-type fuses may have an initial state of an open state and may have a short state after an electrical signal is applied thereto. In contrast, the blowing-type fuses may have an initial state of a short state and may have an open state after an electrical signal is applied thereto. Since the electrical fuse bowing technique can be used at a package level, the electrical fuse bowing technique may be very useful in the repair processes of the semiconductor devices.